(i) Field of the Invention
The present invention relates to an air drier apparatus, and more particularly to an improvement relating to an air drier apparatus for drying compressed air for use in the pneumatic brake system of an automotive vehicle.
(ii) Description of the Prior Art
It has generally been known in the art of pneumatic brake system for use in an automotive vehicle that an air drier is employed to dry air supplied into the pneumatic brake system of an automotive vehicle. For example, there is known as this type of air drier apparatus such a typical construction as shown in FIG. 7, in which an air drier apparatus 100 comprises a housing 101 having an open end at the lower end portion thereof as viewed in FIG. 7, a storage casing 104 disposed in a purge chamber 102 defined within the housing 101 and adapted to enclose a desiccant or drying agent 103 therein, and an end cover 105 adapted to close the open end of the housing 101. This air drier apparatus 100 serves, at the compressed air charging stage on one hand, to relay compressed air from a compressor not shown to an air reservoir by way of a drying agent storage 106 housed in the storage casing 104, a check valve 107 and a purge chamber 102, and serves, at its drier regenerating stage on the other hand, to open a purge valve 108 provided in the end cover 105, thereby allowing compressed air within the purge chamber 102 to be discharged out of the drying agent storage 106 to the atmosphere.
Incidentally, according to a typical construction of a conventional drier apparatus, the drying agent storage casing is mounted in position to the end cover, for instance, by using four screws or the like. On the other hand, the air drier assembly 100 is generally mounted onto the vehicle's framework in such a manner as shown typically in FIG. 8 that for instance two band-like webs or fixing members 109 are used to wrap once around the circumference of the cylindrical housing 101, with the opposite ends 109' of the fixing members 109 being secured together by using such means as screws and nuts, and further being fixed securely using screws and nuts onto the vehicle's framework.
With such a typical construction, the following drawbacks have inevitably been observed in the mounting of the conventional air drier assembly.
Since the drying agent storage casing 104 is mounted in position to the end cover 105 with four screws or the like as noted above, it is then essential, when exchanging (in an overhaul work) the drying agent 103 within the casing, as it got deteriorated after use, to remove all the four screws, which therefore means an additional work for the dismounting of the storage casing.
On the other hand, the drying agent 103 stored in the inside of the drying agent storage casing 104 would have to be exchanged with new one, since it would get deteriorated to lose its hygroscopicity as the air drier apparatus repeats its cycles of compressed air charging and drying agent regeneration during the operation of the braking system, and thus the drying agent storage casing 104 should be replaced regularly or from a rule of thumb. When replacing the drying agent 103 at a regular service interval, it would sometimes be found still serviceable or not deteriorated yet. However, as the air drier apparatus 100 is of a double-shell structure as typically shown in FIG. 8, it would be possible for no one to observe the current state of deterioration of the drying agent 103 from the outside of the drying agent storage casing 104. In this respect, with such construction of the conventional air drier apparatus 100, it would then be inevitable that the drying agent storage casing 104 be replaced with the drying agent 103 being still serviceable, which is undesirable ecnomically.
With the mounting of the air drier apparatus 100 upon the vehicle's framework by way of the fixing members 109, it is apprehended that the air drier apparatus 100 would very possibly drop out of engagement with the fixing members 109 owing to aging thereof or looseness from vibrations of the vehicle during the operation. This is because the air drier apparatus 100 would be in danger of slipping with the mere effect of surface contact with the fixing members 109 forced by the fixing members 109 even if it is secured in position by tightening the two fixing members 109.
In consideration of such drawbacks particular to the conventional construction of mounting of the air drier apparatus as noted above, it would be desirable to attain an efficient resolution for overcoming such inevitable problems particular to the conventional construction.